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Arthur T Knackerbracket has found the following story:
The area of agricultural land that will require irrigation in future could be up to four times larger than currently estimated, a new study has revealed.
Research by the University of Reading, University of Bergen and Princeton University shows the amount of land that will require human intervention to water crops by 2050 has been severely underestimated due to computer models not taking into account many uncertainties, such as population changes and availability of water.
The authors of the study, published in Geophysical Research Letters, argue forecasters and policy-makers need to acknowledge multiple future scenarios in order to be prepared for potential water shortages that would have huge environmental costs.
[...] "If the amount of water needed to grow our food is much larger than calculated, this could put severe pressure on water supplies for agriculture as well as homes. These findings show we need strategies to suit a range of possible scenarios and have plans in place to cope with unexpected water shortages."
[...] The new research suggests that projections of irrigated areas made by the Food and Agriculture Organization of the United Nation and others have always underestimated the amount of irrigation required in future by basing them on other assumptions.
The study highlights that the potential global extension of irrigation might be twice, or in the most extreme scenario, even four times larger than what has been suggested by previous models.
[...] Agricultural land where crops cannot be supported by rainwater alone is often irrigated by channelling water from rivers or springs, sprinkler systems, or by controlled flooding. Increased irrigation in future would mean more water consumption, machinery, energy consumption and fertilisers, and therefore more greenhouse gas emissions.
Journal Reference
A. Puy, S. Lo Piano, A. Saltelli. Current Models Underestimate Future Irrigated Areas, Geophysical Research Letters (DOI: 10.1029/2020GL087360)
(Score: 0) by Anonymous Coward on Wednesday May 06 2020, @07:52PM (1 child)
You are both forgetting many important in human populations. First is that humans don't have distinct generations relative to their lifetime. They overlap to the point where a person can be alive and have grandchildren older than their children. Second is that humans have lived longer over time. Each month of life expectancy adds to the total population of that month due to generational overlap and to the mean number of children per generation by extending reproductive age. Third is that child mortality rate is dropping, meaning that more humans as a proportion of their generation are reaching reproductive age.
Those are just the big three factors and their most obvious ways of affecting human population. There are tons of papers, including the two that TFA cites, on this subject and plenty of free resources online at a simple web or literature search. Feel free to look it up yourself. Many go into great detail as to why an exponential function won't work for human population data.
(Score: 1) by khallow on Wednesday May 06 2020, @10:04PM
None of these items are relevant to the population growth extremes we were discussing.